Endometrial ablation (i.e., the removal or destruction of the endometrial lining of the uterus) is used as an alternative to hysterectomy for treating menorrhagia, or other uterine diseases. One prior technique for performing endometrial ablation employ a resectoscope (i.e., a hysteroscope with a built-in wire loop or other ablative devices) that is inserted transcervically into the uterus, and uses radio-frequency electrical current (RF current) to remove or coagulate the endometrial tissue. These standard techniques typically are performed in a hospital setting.
Some approaches make use of heated fluid to ablate the endometrium. For example, early journal articles describe the use of steam to treat uterine hemorrhage. See, e.g., Van de Velde, “Vapo-“Cauterization of the Uterus,” Amer. J. Med. Sci., vol. CXVIII (1899); Blacker, “Vaporization of the Uterus,” J. Obstet. & Gyn., pp. 488-511 (c. 1901). The use of steam for this purpose was later discredited, apparently due to patient morbidity and mortality. See, e.g., Fuller U.S. Pat. No. 6,139,571. More recent descriptions of the use of injecting hot fluid into the uterus may be found in Goldrath U.S. Pat. No. 5,451,208 and Evans et al. U.S. Pat. No. 5,540,658; U.S. Pat. No. 5,437,629.
Uterine therapies employing a contained fluid have also been described. See, e.g., Quint U.S. Pat. No. 5,084,044; Chin U.S. Pat. No. 5,449,380; Neuwirth et al., “The Endometrial Ablator: A New Instrument”, Obst. & Gyn., 1994, Vol. 83, No. 5, Part 1, pp 792-796. Another balloon-based system using ultrasound as the energy source is described in U.S. Pat. No. 7,004,940. High frequency, or radiofrequency (RF), energy has been used to perform thermal ablation of endometrial tissue. See, e.g., Prior et al., “Treatment of Mennorrhagia By Radiofrequency Heating”, Int. J. Hyperthermia, 1991 Vol. 7, No. 2, pp. 213-220; Stern et al. U.S. Pat. No. 5,443,470; U.S. Pat. No. 5,769,880; U.S. Pat. No. 6,929,642. Current products for performing endometrial ablation include the NovaSure® procedure and a system marketed under the trade name THERMACHOICE®, by Ethicon, Inc. of Somerville, N.J.
Cryogenic ablation, or “cryoablation,” is another endometrial treatment approach. See, e.g., Droegemueller et al. U.S. Pat. No. 3,924,628; U.S. Pat. No. 6,306,129; and U.S. Pat. No. 7,101,367.
Finally, U.S. Pat. Appl. Publ. No. 2004/0068306 describes the use of vapor, such as steam, for endometrial or other tissue ablation, and U.S. Pat. Appl. Publ. No. 2002/0177846 describes the use of vapor for treating uterine fibroids.